There have been so far proposed various types of a seat sliding device for a vehicle. For example, a seat sliding device for a vehicle disclosed in Patent Document 1 is provided with a lower rail which has an opening that is opened upward, the cross section of which is substantially U-shaped, and an upper rail which blocks the opening, the cross section of which is substantially U-shaped. The lower rail engages with the upper rail to slide with each other in a longitudinal direction. And, a lock lever is supported on the upper rail.
That is, the lock lever is provided with a rivet arranged inside a U-shaped cross section of an attachment part of the lock lever and a spring pin, which penetrates through the attachment part, and also the rivet in a widthwise direction. The rivet is crimped and joined to a top plate of the upper rail, by which the lock lever is coupled to the upper rail to rotationally move about the spring pin.
The lock lever is integrally provided with a latch part which is capable of entering into notches formed at a lower part of the upper rail in association with rotational movement about the spring pin. The latch part spreads substantially all over the upper rail in the widthwise direction thereof. Then, a lock hole into which a latched part that is formed on the lower rail can be fitted in association with the rotational movement of the lock lever about the spring pin is formed at the latch part.
The lock lever is connected to an operating lever which is inserted from a distal end part of the upper rail. Further, a lock spring composed of blade springs is provided with one end part which is held between the top plate of the upper rail and the rivet. The lock lever is pressure-contacted by the other end part of the lock spring and thereby constantly urged in a direction in which the latch part of the lock lever enters into the notches of the upper rail and also in a direction in which the latched part of the lower rail is fitted into the lock hole.
Therefore, the lock lever is urged by the lock spring to rotationally move, the latch part thereof enters into the notches of the upper rail and the latched part of the lower rail is also fitted into the lock hole. Thereby, restrictions are placed on movement of the upper rail which supports the lock lever with respect to the lower rail. Accordingly, restrictions are placed on movement of a seat with respect to a vehicle floor in the longitudinal direction of the rails. In other words, the seat is locked.
On the other hand, a release operation force is input from the operating lever. Thereby, when the lock lever rotationally moves against an urging force of the lock spring in a direction in which the latch part of the lock lever is detached from the notches of the upper rail and also in a direction in which the latched part of the lower rail is detached from the lock hole, restrictions on movement of the upper rail with respect to the lower rail are released. Thereby, the seat is allowed to move to the vehicle floor in the longitudinal direction of the rails. In other words, the seat is unlocked.
As so far described, it is possible to adjust and retain the seat at such a required position, at which a passenger sits favorably.
Further, for example, a seat sliding device for a vehicle disclosed in Patent Document 2 is provided with a lower rail which has a flange part and an upper rail which holds the flange part. A cut is formed at a top plate part near both ends of the upper rail and a cut-out part is also formed at each end of an inner edge of the flange part of the lower rail. In the above-described structure, when the lower rail and the upper rail are assembled, the cut of the upper rail is folded inward after insertion of the lower rail into the upper rail to form a folded part. Then, on movement of the upper rail with respect to the lower rail, the folded part of the upper rail is brought into contact with and latched to a step which is formed by the cut-out part of the lower rail. Thereby, a distance of relative movement between the lower rail and the upper rail is restricted within a predetermined range.